FR2585424A1 - DIAPHRAGM CLUTCH MECHANISM, IN PARTICULAR FOR A MOTOR VEHICLE - Google Patents

Abstract

THE INVENTION RELATES TO A DIAPHRAGM CLUTCH MECHANISM INCLUDING A COVER 1, AT LEAST ONE PRESSURE PLATE 5, A DIAPHRAGM 6 AND ASSEMBLY MEANS SUBJECTING THE DIAPHRAGM 6 TO THE COVER 1, THE SAID ASSEMBLY MEANS INCLUDING SHARE OF RETAINERS ATTACHED TO THE COVER 1 HAVING AN AXIAL PART 14 THROUGH THE DIAPHRAGM 6 AND AN END WING 15 BENDED IN FAVOR OF A BLEED 16 PRESENTED BY AXIAL PART 14, DEFINING WITH THE SAID AXIAL PART A SHIM ELBOW , AND ON THE OTHER HAND A CROWN 13 WEDDED IN THE TIMING ELBOW. FOLLOWING THE INVENTION THE CROWN 13 IS OF TRUNCONIC SHAPE WITH A ROUNDED EXTERNAL EDGE 21 FORMING SECONDARY SUPPORT 17 AND INTERNAL CORE 22, 23 RESPECTIVELY IN CONTACT WITH THE AXIAL PART 14 AND THE END WING 15 OF ONE AU LESS RETAINERS. APPLICATION IN PARTICULAR TO MOTOR VEHICLES.

Description

The present invention relates generally to the mechanisms

  diaphragm coupling, particularly for a motor vehicle, of the kind comprising a first generally annular part, called a cover, at least one plate, called a pressure plate, designed to be secured in rotation with the cover by being movable relative to it; ci, a second generally annular piece, called diaphragm, comprising a Belleville washer peripheral portion, for action on the pressure plate, and a central portion fragmented radial fingers, for action of a release stopper, and means for assembly pivotally fastening the diaphragm to the cover by axially applying said diaphragm, with an elastic clamping load, constantly against a primary bearing carried by the cover, said connecting means comprising, on the one hand, retaining members coupled to the cover having an axial portion passing through the diaphragm through passages formed between the radial fingers of the diaphragm ui-ci and an end flange, bent in favor of a groove that has the axial portion, defining with said axial portion a wedging wedge and, secondly, a ring wedged in said wedge rigging and adapted to arrange for the diaphragm a secondary support arranged

  substantially in relation to primary support.

  Such a clutch mechanism is adapted to be attached by its cover on a plate, said reaction plate, integral with a first shaft, generally a driving shaft, with insertion between the reaction plate and the pressure plate of a friction disc integral in rotation with a second shaft, generally a driven shaft, while around it is arranged a part, called a release stop, capable of acting on the radial fingers of the diaphragm, for controlling in disengagement of the clutch thus formed, which is normally engaged; the pressure plate in such a position clamping the friction disk against the reaction plate under the bias of the peripheral portion forming a washer

  Belleville of the diaphragm relying on primary support.

  Such a clutch mechanism is described in the French patent application 76 05 485 of February 27, 1976 and comprises on the one hand retaining members, relatively thin and flat, and on the other hand a crown, which is centered on the axial portion of said retaining members by the edge of its inner periphery having a substantially flat radial orientation portion in contact with the wedge. In addition, said ring has at its outer periphery a very open V-shaped part for forming the secondary support and for stiffening said ring. Thus this crown has a tortuous shape with a radial portion in section, an inclined portion and another portion inclined in sense

inverse of the previous one.

  Such a device has given and still gives satisfaction. This device nevertheless has the disadvantage of having a ring of relatively high stiffness and of applying to said ring, for a constant maintenance of the diaphragm on the primary support, an important prestress which increases all the more the effect of hysteresis of the diaphragm when it tilts between the primary and secondary supports and leads to the inevitable wear in service of the diaphragm and supports, between which it is mounted tilting, of

large load variations.

  To overcome these drawbacks it may be thought to replace this ring by a thinner spring steel crown, as described in the German patent application 28 43 317 of October 4, 1978, but such a solution is expensive and the crown does not. is not entirely located radially beyond the axial part of the

  retainers, which complicates the assembly.

  The present invention generally aims to overcome these disadvantages and thus to create a device that reduces the clamping load

  axial using an economical solution.

  According to the invention this diaphragm clutch mechanism of the above type is characterized in that the ring is of frustoconical shape with a rounded outer edge forming secondary support and internal edges in contact respectively with the axial part and the wing. end of at least one of the retaining members. Thus, going against the conventional wisdom that the inner periphery of the radially oriented crown was necessary not only for

  a good centering of said crown but also for counter

  carrer an action of opening thereof during the folding of the end wing, in combination with the stiffening of the outer periphery of said ring by the V-shaped part, the present invention makes it possible to obtain a production crown simplified and therefore lower cost, while having a good accuracy of clamping thanks to the bleeding of the retainers and a reduction of

  manufacturing tolerances of said crown.

  According to another characteristic of the invention the

  inner slice of the crown is rounded.

  With this arrangement the rounded inner edge of the ring can slide axially along the axial portion of the retaining members during the folding operation of the end wing without risk of incrustation. According to another characteristic, the clutch mechanism is characterized in that the groove has a trapezoid profile in section, said groove having a

  flat bottom between two inclined lateral sides.

  This arrangement is particularly advantageous in combination with the ring crown according to the present invention, because it allows a bending of the upper end flange at 90 and formation of a wedging wedge having in axial section an acute angle. An additional possibility of deformation of the ring crown is thus provided, which makes it possible, by modifying the angle of the truncated cone thereof, to obtain a better precision in the value of clamping of the diaphragm between its primary supports and secondary. The objects of the present invention, their characteristics and their advantages will emerge from elsewhere

  the following description, by way of example, in

  reference to the attached schematic drawings in which: FIG. 1 is a view, in axial section, of a mechanism

clutch according to the invention.

  FIG. 2 is a view, on a larger scale, of a detail of FIG. 1 corresponding to the inset II of this

figure 1.

  Figure 3 is a partial view in axial section relating to a retaining member before folding its end. 15. FIG. 4 is a partial view in axial section of a

  variant of the crown according to the invention.

  The clutch mechanism according to the invention generally comprises, as can be seen in FIG. 1, a first generally annular part 1 called a cover, provided at its outer periphery with a first series of coplanar areas 2 through which it is likely to be fixed on a plateau, said reaction plate or flywheel (not shown), and a second series of coplanar beaches 3, set back from the previous ones, by which it is coupled by tabs 4 to a second plate 5, called pressure plate, a second generally annular part 6, called diaphragm, comprising a peripheral portion 7 forming a Belleville washer for action on the pressure plate 5 and a fragmented central portion in radial fingers 8 separated, two by two , by slots 9 issuing from passages 10 formed between the fingers 8, in the zone according to which these are connected to the peripheral portion 7 forming a Bellevill washer e of the diaphragm

  6 whose outer periphery acts on the plate 5.

  The tabs 4 solidarise in rotation the tray-

  with the courvercle 1 while allowing said plateau a

  axial mobility with respect to the lid 1.

  The second generally annular part 6, called the diaphragm, is interposed axially between the cover 1 and the pressure plate 5 so as to allow a friction disc, not shown here, interposed between the pressure plate 5 and the reaction plate or flying, to be clamped between them under the solicitation of said diaphragm. It is on the radial end of the radial fingers 8 of the diaphragm 6 closest to the axis of the mechanism that is likely to act a movable control part, said release stop, whose action direction is schematized in FIG. 1 by the arrow A. Assembly means are provided for pivotally securing the diaphragm 6 to the lid 1 with an elastic clamping load which is constantly holding it against a primary bearing 11 carried by the cover 1 and constituted by , in the example shown, by a stamped

cover 1.

  As can be seen in FIG. 2, these assembly means comprise, on the one hand, retaining members 12, relatively thin and flat, distributed circularly, coupled to the cover 1 and, on the other hand, a ring 13 wedged by these retaining members. . More particularly, these members comprise an axial portion 14 crossing the

  diaphragm 6 thanks to the passages 10 made in this

  ci in the vicinity of the root of the radial fingers 8 and an end flange 15, bent in favor of a groove 16 that has the axial portion 14, defining a wedging wedge with said axial portion. Here, these retainers are therefore radially thin and circumferentially elongate and are integral with the

  folded cover at its primary support 11.

  In this bend is wedged the ring 13 which therefore extends radially entirely beyond the axial portions and which forms for the diaphragm 6 a secondary support 17, disposed substantially opposite the primary support 11

formed by the lid.

  In practice and as illustrated in Figure 3, before assembly of such a diaphragm clutch mechanism, the end flange 15 of the retaining members 12 is straight and parallel to the axis of the assembly. being

  in alignment with the axial portion 14.

  For formation of the end flange 15, the retaining members 12 are assigned transversely over their entire width a groove 16, open in the direction opposite to the axis of the assembly, which locally reduces the thickness and which has, in section, a trapezoidal profile having a flat bottom 19 between two inclined lateral sides 20. As a result, the fold line is materialized by this groove 16. It should be noted that the depth of the kerf is between 0.15 and 0.30, e being

the thickness of the paw.

  As can be seen in FIG. 2, and according to the invention, the ring 13 is of frustoconical shape with, on the one hand, a rounded outer edge 21 forming a secondary support 17 which facilitates the tilting of the diaphragm and which, during its manufacture, has undergone hardening improving the wear resistance of the secondary support and, on the other hand, internal edges 22, 23, respectively in contact with the axial portion 14 and the wing

  end 15 of at least one of the retaining members 12.

  Thus after engagement, on a retaining member 12, the diaphragm 6 and the ring 13, the end 15 is folded radially in contact with the ring 13, as shown in Figure 2, here a right angle, and in the direction opposite to the axis of the assembly so as to obtain the device according to Figure 2. If necessary, the folding can be done at an angle greater or less than a right angle, this being made possible by the shape of the groove 16 trapezoidal and by cooperation of the wing 15 and the edge 23, the other edge 22 sliding on the part

  axial during this operation.

  At the end of such a folding of the end flange 15, these retaining members 12 apply to the ring 13 a preload which has a load greater than that of the diaphragm 6 at the disengagement stop A and maintain so constantly the diaphragm 6 and more particularly the inner peripheral part of its

  Belleville washer against the primary support 11.

  This arrangement allows the crown 13 to be centered by virtue of its internal edge 22 and to obtain, during the folding operation of the end wing 15, thanks to its internal edge 23, the farthest from the diaphragm, a

  precision of the clamping force of said crown.

  Thanks to this, it is not necessary to use a spring steel crown, only a sheet metal crown is sufficient. According to the variant of Figure 4, the ring 13 is of frustoconical shape with a rounded outer edge 21 forming secondary support 17 and at its inner periphery a rounded edge 25, with internal edges 22, 23, respectively in contact with the axial portion 14 and the wing

  end 15 of at least one of the retaining members.

  Therefore, during the folding operation of the end flange 15, the inner edge 22 will not tend to become embedded in the axial portion 14 but on the contrary thanks to the rounded slice 25 of sliding along

said part.

  As is evident from the description,

  for the same lid, the thickness of the crown will be

  depending on the desired value of the diaphragm tightening.

  In practice the thickness of the crown is at least equal to half the thickness of the axial portion 14 of the

  legs being close to said half.

  Of course, the invention is not limited to the embodiments described and shown but embraces all variants. In particular, the primary support 11 of the cover 1 can be formed by a stamped, as shown, or by an open or closed snap ring

  in a groove that presents the lid.

  It is the same for the assembly means which may comprise retaining members directly from the cover and forming with it a single piece, or retaining members, independent of each other, distributed circularly, which have, in addition to their end flanges serving to hold the ring in contact with the Belleville washer, another end flange serving to press the retaining member against the cover on the face thereof opposite to that which is in view of the diaphragm, or individual retaining members connected to each other by a common barrette, which extends circumferentially bearing against the cover on the face thereof opposite to that which is opposite

of the diaphragm.

  In addition it will be noted that the crown according to the present invention is mounted on the covers with parts

  retainers with bleeds of the prior art.

  As will be understood the position of the grooves and the value of the inclination of the crown are determined for each application so that no interference occurs with the diaphragm during

the operation of it.

Claims (3)

  1) diaphragm clutch mechanism, in particular for a motor vehicle, of the type comprising a first generally annular part called said cover (1), at least one plate called pressure plate (5) intended to be secured in rotation with the cover (1) while being   mobile with respect to it, a second piece -   generally annular, said diaphragm (6), having a Belleville washer peripheral portion (7) for action on the pressure plate, and a fragmented central portion radial fingers (8) for action of a release stop, and assembling means pivotally securing the diaphragm (6) to the cover (1) by axially applying said diaphragm (6) with an elastic clamping load constantly against a primary bearing (11) carried by the cover (1), said assembly means comprising on the one hand, retaining members coupled to the cover (1) having an axial portion (14) passing through the diaphragm (6) through passages (10) formed between the radial fingers (8) of it and an end wing (15), folded in favor of a groove (16) that has the axial portion (14), defining with said axial portion a wedging wedge, and on the other hand a crown (13) wedged in said elbow and adapted to provide for the diaphragm (6) a secondary support (17) disposed substantially opposite the primary support (11), a clutch mechanism characterized in that the ring (13) is of frustoconical shape with a rounded outer edge (21) forming secondary support (17) and inner edges (22, 23) in contact with the axial portion (14) and the end wing (15) of at least one retainers.   2) clutch mechanism according to claim 1 characterized in that the inner edge (25) of the crown (13) is rounded.   3) Clutch mechanism according to any one of   Claims 1 and 2, characterized in that the bleeding (16)   has in section a trapezoidal profile, said groove having a flat bottom (19) between two lateral flanks inclined (20).